import java.util.*;
class Example2_5 {
	public static void main (String args[]) {
		int start=0,end,middle;
		int a[]={12,45,67,89,123,-45,67};
		int N=a.length;
		for(int i=0; i<N; i++) {
			for(int j=i+1; j<N; j++) {
				if(a[j]<a[i]){
					int t=a[j];
					a[j]=a[i];
					a[i]=t;
				}
			}
		}
		Scanner scanner = new Scanner(System.in);
		System.out.println("输入整数，程序判断该整数是否在数组中:");
		int number = scanner.nextInt();
		int count = 0;
		end = N;
		middle = (start+end)/2;
		while(number!=a[middle]){
			if(number>a[middle])
				start=middle;
			else if(number<a[middle])
				end=middle;
			middle=(start+end)/2;
			count++;
			if(count>N/2)
				break;
		}
		if(count>N/2)
			System.out.printf("%d不在数组中.\n",number);
		else 
			System.out.printf("%d在数组中.\n",number);
	}
}
